Java: Does an endless loop eventually lead to a StackOverflowError?

Question

I'm currently reviewing for my OCPJP 6 using the Sierra & Bates reviewer. I stumbled upon a question regarding an endless loop not throwing a StackOverflowError. As far as I've learned, it should throw it eventually.

Please refer to this PDF for the question: https://java.net/downloads/jfjug/SCJP%20Sun%20Certified%20Programmer%20for%20Java%206-0071591060.pdf

Question I'm referring to is from Self Test Chapter 5 Question 9 (page 455 of the PDF).

I answered, CDF. The correct answer, according to the book was DF. It was also explained in there that case 0 initiates an endless loop, not a StackOverflowError.

True, it does initiate an endless loop, but eventually turn out to be a StackOverflowError. The answer C stated "might throw a StackOverflowError" so I knew C was correct.

If I'm wrong, can anybody explain why?

This `for(;;);` is an endless loop. Why would it cause `StackOverflowError`? Does it take up more and more of the stack every iteration? — Sotirios Delimanolis, Feb 08 '14 at 17:36
Endless (or even finite with high-bound) recursive call results an Stack Overflow, not a loop. — Amir Pashazadeh, Feb 08 '14 at 17:40
Offtopic, but you do know that PDF is for sun certified java programmer certification, which doesn't exist anymore as such? Oracle split that into two distinct certifications. — eis, Feb 08 '14 at 18:07

score 5 · Accepted Answer · edited May 23 '17 at 10:33

5

Since, in that loop, you're not actually calling methods that need to call other methods (a la recursion), you're not adding more calls to the stack. You're merely repeating the steps you did most every time through.

Since a StackOverflowError is only invoked in certain conditions - namely, the calling of another method (which would call more methods), or the allocation of more elements onto the stack, then there's really no way that this particular loop could cause such an error.

edited May 23 '17 at 10:33

Community

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answered Feb 08 '14 at 17:41

Makoto

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Thank you for the clarification! I must have missed that. – mpmp Feb 09 '14 at 13:18

score 1 · Answer 2 · answered Feb 08 '14 at 18:03

The stack overflows is commonly :- excessively deep or infinite recursion.
In simple terms,for an example: calling a method within a method.

        public static void proneToStackOverFlow() {
         proneToStackOverFlow();
        }

        public static void main(String[] args) 
        {
            proneToStackOverFlow();
        }

Java: Does an endless loop eventually lead to a StackOverflowError?

2 Answers2